package problem852;

//852.山脉数组的峰顶索引
//https://leetcode.cn/problems/peak-index-in-a-mountain-array/

class Solution {
    public int peakIndexInMountainArray(int[] arr) {
        int left = 1, right = arr.length-1-1;
        while(left < right) {
            int mid = left + (right - left)/2;
            if(arr[mid-1] < arr[mid] && arr[mid] < arr[mid+1]) {
                left = mid + 1;
            }else {
                right = mid;
            }
        }
        return left;
    }
}